With the advent of plastics technology there has been movement in the container industry from metal storage cans or containers to like products made out of plastic. Such change in materials of construction has led to problems in the art of sealing the plastic containers to prevent spillage or leakage since such plastic containers are more pliable and lack the rigid construction of the metal container. The plastic containers appear to be more susceptible to accidentally opening when dropped or leaking when they are roughly handled during transfer operations.
Many solutions have been advanced to alleviate these problems, by the development of interlocking sealing assemblies. One such assembly is a single interlocking seal to attempt to prevent such occurrences as disclosed in U.S. Pat. No. 3,840,144 to Dry.
A further development is disclosed in U.S. Pat. No. 4,210,258 to von Holdt wherein there is exhibited a double interlocking seal on a plastic cover and container. The addition of the second interlock appears to overcome some of the problems that have existed.
All such prior art sealing assemblies require that an individual when attempting to open the container must apply a force with a flat edge object a plurality of times around the peripheral edge of the cover of the container. This procedure can once again lead to the problem of accidental spills since it is necessary to rotate the container to reach the point where force will be applied.